On the other side, someone mention Pascal's Wager: storing a few basic needs and self defense weapons (were legal), costs practically nothing now but it could save your family's life. It's not a sure way but it's much better to have them then not.
Even in cramped apartments you could store stuff for a week or two; in private homes, you're talking months. IIRC, tap water in dark areas with a drop of bleach for liter will last for quite a while. Think 55gallon drums, replaced every so often.